added Federated Graphite recipe example
added federated recipe bats tests
Bugfix: No such file or directory relay-rules.conf
graphite_web attributes merged into default due to attribute dependency in uri and file_path
added the whisper-clean.py script for whisper node data cleaning
added whisper-clean-this-node.sh for helping on whisper database cleaning
Merge pull request #74 from onddo/federated-recipe

Federated recipe and whisper-clean.py script